What you are trying to accomplish with the way you have implemented two variables into the url won't work, because one or the other may not exist, you need to test certain conditions before stamping a direct/file/ as existent, and readable. Firstly you need to check if the directory exists, then check if its readable, followed by checking if the file exists. If all those conditional statements prove to be true, then you can construct your url as such
$file = '/var/www/html/public_html/svsshc/'$_date'/'.$_REQUEST['id'].'.png';
Also where is your $_date variable coming from? Is it from a database,user input, external data, local...etc